DIY engine mods!
Turbo Mini Forums

Yo. Ive recently brought a Mini City, 1.0 litre jobby off a friend of a friend. I also have a 1991 mini cooper engine to put under the bonnet. I work in an engineering company, and have access to all manner of jig boring machinery, honing, lathes, u name it! i wanna bore out the engine block, cylinder head etc, but have no idea what sizes everything should be! I was looking at making it a 1380, and then adding a turbo unit aswell, havent got a clue where to start tho..........help needed! cheers guys

Hello and welcome!

If I were you, I'd have a look at the specs of other peoples cars and decide what you really want to build.

Most turbo engines are only bored +20 thou to give 1293cc this is because large overbores such as 1380cc engine can suffer from bore flex on a turbo engine.
That said there are a few people who have sucessfully done it!

If your totally new to mini's then perhaps have a read of a tuning manual such as David vizards book etc.
It's a bit old now and not so much turbo stuff in it, but its a good place to start learing about the a-series engine.

I'm sure you'll get a lot of advice of the others on here!

Vizards book is your source of all you need to know.
Read it, then read it again. And again.

Getting the blocks bored and honed to 1380 is not a job for amateurs though... Offset boring is needed for any kind of reliability... Personally, i'd ship it out to be bored/honed (will cost around £80 for offset 1380) and then use your skills to machine the other stuff like the deck, main cap, etc...